/**
 * 求hours内和是24的倍数的有序对
 * O(N^2)即可
 */
class Solution {
public:
    int countCompleteDayPairs(vector<int>& hours) {
        int n = hours.size();
        int ans = 0;
        for(int i=0;i<n;++i){
            for(int j=i+1;j<n;++j){
                if(0 == (hours[i] + hours[j]) % 24){
                    ans += 1;
                }
            }
        }        
        return ans;
    }
};